The subject matter of the present invention relates to packers used in association with oil exploration, and more particularly, to a hydraulically set packer adapted to be used in association with independently set straddle packers, to a hydraulic ratchet used in association with compression set straddle packers, and to an inflate deflate valve used in association with inflatable straddle packers.
In certain circumstances, one packer, disposed around a tubing in a borehole, should be set independently of the setting of another packer disposed around the tubing in the borehole. For example, a pair of straddle packers may be disposed around a tubing in a borehole, the straddle packers being either inflatably set or compression set. Circumstances may arise where a third packer, also disposed around the tubing, should be set independently of the setting of either straddle packer. Therefore, there is a need for a third packer which may be set hydraulically, and not by inflation or compression. Furthermore, if the straddle packers are inflation set, when it is necessary to deflate the inflated straddle packer, it is possible that the packer may not deflate normally, as it should. Consequently, an alternate means is required for deflating the inflated straddle packer. On the other hand, if the straddle packer is compression set, a top straddle packer on the tubing should not be set until a bottom straddle packer on the tubing is first set. Consequently, a means is required for setting the top straddle packer only when the bottom straddle packer is first set.